Track type work machines are typically employed in construction, mining, oil and gas, forestry and in other rugged operating environments. Rather than wheels, such work machines utilize tracks disposed one on each side of a work machine body, and consisting of a chain of coupled links which typically extend about a drive sprocket and one or more idlers. The tracks or “track chains” engage the ground and enable the work machine to move about over relatively rough terrain.
The track chains themselves typically include movable metal links coupled together. Over the course of many hours of operation, the constant metal to metal contact of the moving track chain components can result in significant wear, even where bearings and lubricating oil are used to reduce friction among the components. Galling and other wear related problems tend to be particularly prevalent with relatively large track type work machines, which may subject the track chain components to substantial loads. In some instances, large loads may actually cause the pins supporting the track chain bearings to flex, compounding wear problems by imparting a disproportionate load to isolated regions of the bearing assembly, and thereby causing acute wear. Loads tending to urge the bearing assembly pin or portions of the track sideways relative to a work machine travel direction are known in the art as side loads, and have heretofore been especially difficult to manage. Side loads can actually cause adjacent portions of the track links to grind together.
One joint design directed to limiting certain types of wear in a track chain is known from U.S. Pat. No. 6,485,116 to Oertley. Oertley employs sleeve bearings positioned about a pin, and interacting with a central bushing. The sleeve bearings are crowned to assist in directing certain loads toward a center thereof, reducing disproportionate loading. While Oertley represents one successful approach for at least certain load types, there is always room for improvement.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.